module decoder #(
    parameter KW = 3
) (
    input [KW-1:0] din,
    output [2**KW-1:0] dout
);

  logic [2**KW-1:0] out;
  always_comb begin
    out = 'b0;
    out[din] = 1'b1;
  end
  assign dout = out;

endmodule
